Suboptimal diabetes management (DM) is an important factor in the development of poor metabolic control. Adolescence and young adulthood are developmental periods marked by increased risk for poor DM. Therefore, interventions to improve illness management difficulties in older adolescents and young adults (OAYA) with T1D have the potential to significantly improve health outcomes and quality of life. Exposure to stress significantly increases vulnerability to poor health outcomes. A significant body of both cross-sectional and longitudinal studies demonstrates that stress affects both DM and metabolic control in persons with T1D. Despite the large number of studies showing the importance of reducing stress, to date, stress management interventions have been ineffective in improving health outcomes for adolescents and adults with T1D. There are two significant problems with stress management treatments as currently applied to T1D. First, CBT-based interventions have largely relied on participant self-report to determine which life events are causing stress and, thus, impairing DM. However, self-reports of illness management behaviors are notoriously biased/inaccurate. Therefore, stress management interventions for OAYA may have unsuccessful not due to the ineffectiveness of cognitive behavioral treatment approaches per se, but rather due to inadequate targeting of those stressors that are most responsible for derailing DM. Second, a new generation of behavioral therapies called mindfulness approaches focus on changing the meaning of psychological events that people experience, rather than on changing or modifying the events themselves. Therefore, effective stress management interventions for OAYA with T1D may also need to utilize new treatment strategies such as mindfulness. The goal of the proposed study is to develop a potent diabetes management intervention for OAYA aged 16-20 with T1D using a phased approach to intervention development. In Phase 1, we will use an innovative technology (Electronically Activated Recorder; EAR) to more accurately identify stressors that affect DM in OAYA with T1D. In Phase 2, we will use this data to adapt existing CBT interventions previously used with OAYA to increase their efficacy. We will also adapt a mindfulness approach (Mindfulness Based Stress Reduction; MBSR) for use with OAYA with T1D. Next, we will test for signals of efficacy for each of the two approaches to reduce stress and improve DM, as well as evaluating implementation feasibility and satisfaction rates. In Phase 3, we will conduct a pilot randomized clinical trial (RCT) among OAYA with poorly controlled T1D comparing the most successful Phase 2 stress management approach to an attention control condition. PUBLIC HEALTH RELEVANCE: Older adolescents and young adults with poor diabetes management are at high risk for short and long-term diabetes complications and are also heavy users of health care dollars. The primary purpose of the proposed study is to develop and test the efficacy of a novel stress management intervention to improve diabetes management using a phased approach to intervention development. If successful, the stress management intervention would have the potential to improve health outcomes and quality of life in a vulnerable population.